Petrosal ganglion responses to acetylcholine and ATP are enhanced bychronic normobaric hypoxia in the rabbit

Abstract

tIn mammals, adaptation to chronic hypoxia requires the integrity of the arterial chemoreceptors, speciallythe carotid body (CB). Chronic hypoxia increases the sensibility of the CB by acting on the receptorcells, but there is limited information on the effects of chronic hypoxia on the sensory neurons thatinnervate the CB. Therefore, we studied the responses evoked by ACh and ATP, the main transmittersthat generate the chemoafferent activity, on the petrosal ganglion (PG) of rabbits exposed to chronicnormobaric hypoxia (CNH) during fourteen days. ATP and ACh increased the activity of PG neurons ina dose-dependent manner, in a similar way than in rabbits not exposed to hypoxia (naïve). However,the duration of the responses were significantly increased by CNH, with the mean maximal responses toACh and ATP increased by a factor of two and four, respectively. Our results suggest that CNH increasesduration of the responses by modifying the expression and/or content of ACh and ATP receptors.